1. Technical Field
The present disclosure relates to a vehicle control apparatus for a vehicle including an automatic transmission having a torque converter provided with a lock-up clutch.
2. Related Art
Some of vehicles including an automatic transmission having a torque converter provided with a lock-up clutch perform so-called kick-down control in response to strong depression of the accelerator pedal by a driver. The kick-down control changes the transmission gear ratio to a lower rate (down-shift) to increase the torque in response to change of an accelerator opening or an accelerator opening rate to a predetermined value or greater. Also, at the time of kick-down, lock-up disengagement (engagement of the lock-up clutch is disengaged) along with the down-shift is performed, thereby producing a torque amplification effect by the torque converter to achieve further increase of the torque (see, for instance, Japanese Unexamined Patent Application Publication Nos. 2014-231894 and 7-243517, and Japanese Patent No. 5169920).
Although the kick-down control is completed in response to return of the accelerator pedal to the original position, when a driver feels that sufficient acceleration is not obtained by the kick-down control or when further acceleration is needed during acceleration by kick-down (for instance, passing or merging with traffic), the driver may request kick-down for the second time by further depressing the accelerator pedal. Hereinafter a kick-down request made for the second time during the kick-down control is referred to as a “second-time kick-down request”. It is presumed that a driver making a second-time kick-down request feels sufficient acceleration feeling is not obtained through the last kick-down request or wants to obtain acceleration feeling again supposed to be achieved by kick-down. However, in order to avoid louder engine noise due to entering of the number of engine revolutions into a high-rotational region and to avoid up-shift immediately after down-shift, the down-shift amount at the time of a second-time kick-down request is preferably set to be small. For this reason, the following setting is hardly made: the amount of down-shift is increased and sufficient acceleration feeling is obtained by increase in driving force or the number of engine revolutions. Therefore, sufficient acceleration feeling is not obtained through a second-time kick-down request and the driver may feel sense of considerable incongruity.